Adaptive pathway development for Fabry disease: a clinical approach.

Fabry disease (FD) is a rare X-chromosome-linked lysosomal storage disorder. Although initial expectations of enzyme replacement therapy (ERT) were high, it is now clear that real-world effectiveness is disappointing and evidence gathering has been inadequate. In retrospect, development of ERT for FD had several shortcomings. Little convincing evidence on the effectiveness existed at time of authorization. Also, post-marketing evaluation failed to generate sufficient and relevant data for adequate evaluation on effectiveness. Adaptive pathways might have benefitted ERT development by: (i) involving healthcare professionals, patients, health technology assessment bodies and payers in the development process; (ii) iterative development, starting with initial authorization in classical males; (iii) a clear real-world data collection plan; (iv) an independent disease registry; and (v) prescription control.